Rotary kiln assemblies, which may be used for gas/liquid/solid counter or co-current reactions comprise an inlet arrangement, the rotary kiln itself and an outlet arrangement. It is to be understood that materials can be fed into or extracted from either the inlet arrangement or outlet arrangement. Seal arrangements are needed between the inlet arrangement/rotary kiln and between the rotary kiln/outlet arrangement so that loss of valuable materials can be avoided and, in the case of unpleasant or toxic substances, escape of materials may be prevented.
Rotary kiln assemblies contain materials which may have to react at hundreds of degrees Celsius, so that thermal expansion of the rotary kiln must be taken into account during design of the rotary kiln assembly. There is, however, a problem because thermal expansion takes place, and different parts of the kiln assembly are heated to different temperatures causing temperature gradients and the possibility of differing non-axial thermal expansion movement of different parts of the assembly, which can allow damage to the aforementioned seal arrangements, making loss of materials and plant down-time a possibility.
An object of the present invention is to seek to provide a method of and apparatus for monitoring a rotary kiln assembly so that, when necessary, the aforementioned problem can be mitigated.